A CLASSIFICATION OF INFLAMMATORY DISORDERS OF THE SKIN AND SUBCUTIS The Epidermis: Spongiotic dermatitis: Allergic contact dermatitis Photoallergic reactions Nummular eczema Superficial erythema annulare centrifugum Pityriasiform dermatitis, including: Pityriasis rosea Pityriasis lichenoides (spongiotic variant) Pityriasiform drug eruptions Giannott-Crosti Seborrheic dermatitis, acute Miliaria Stasis dermatitis Pruritic urticarial papules and plaques of pregnancy Eosinophilic spongiosis and its differential diagnosis, including: Incontinentia pigmenti Allergic contact reactions Pemphigus Pemphigoid Herpes gestationis Dermatitis herpetiformis Atopic dermatitis Drug reactions Polymorphous light eruption Perniosis Psoriasiform dermatitis: Psoriasis Seborrheic demraitits, chronic Pityriasis rubra pilaris Lichen simplex chronicus Interface dermatitis: Cell-poor vacuolopathic interface dermatitis Eosinophils absent Superficial vascular plexus injury present: Dermatomyositis Systemic lupus erythematosus, anti-Ro +ve Sjogren's syndrome, anti-Ro/La +ve Mixed connective tissue disease Superficial vascular plexus injury absent: Systemic lupus erythematosus Subacute cutaneous lupus erythematosus Discoid lupus erythematosus (occasional case) Relapsing polychondritis Graft-versus-host disease, acute Jessner's lymphocytic infiltrate (rare case) Polymorphous light eruption (rare case) Phototoxic eruptions Erythema multiforme Eosinophils present Superficial vascular plexus injury present: Dermatomyositis (occasional case, especially drug- or viral-related) Superficial vascular plexus injury absent: Superficial erythema annulare centrifugum Erythema multiforme Delayed type hypersensitivity reaction (rare) Graft-versus-host disease, acute (occasional) Polymorphous light eruption (rare case) Lupus erythematosus, drug-induced Phototoxic eruptions Erythema multiforme Lichenoid interface dermatitis Eosinophils absent: Lichen planus Subacute cutaneous lupus erythematosus Discoid lupus erythematosus Mixed connective tissue disease Graft-versus-host disease, chronic Delayed type hypersensitivity reactions, including Insect bite reactions (occasional case) Drug reactions (i.e. drug-iduced subacute lupus erythematosus) Post-viral (i.e. post-Herpetic) eruptions Lichenoid keratoses, including Benign lichenoid keratosis Lichenoid actinic keratosis Lichenoid seborrheic keratosis Porokeratosis Pityriasis lichenoides Eosinophils present: Delayed type hypersensitivity reactions, including Insect bite reactions Drug reactions, lichenoid (i.e. diuretics, antihypertensives, fixed drug eruptions) Allergic contact reactions, lichenoid (i.e. photodevelopers) Post-viral (i.e. post-Herpetic) eruptions Lichenoid keratoses, including Benign lichenoid keratosis Lichenoid actinic keratosis Lichenoid seborrheic keratosis Porokeratosis Graft-versus-host disease, chronic The Dermis: Lymphocytic dermal infiltrates (with minimal or no epidermal alteration) Erythema annulare centrifugum (superficial and deep variant) Delayed type hypersensitivity reactions, including Insect bite reactions (rare case) Dermal allergic contact reactions (i.e. nickel) Atopic dermatitis Drug reactions Jessner's lymphocytic infiltrate, classical Tumid lupus erythematosus Steroid-treated connective tissue diseases of diverse types Morphea and morpheiform tissue reactions Malignant lymphoma, B-cell and T-cell types (angiotropic T-cell lymphoma, tumor stage mycosis fungoides, angioimmunoproliferative diseases) Lymphomatoid connective tissue diseases Lymphocytic dermal infiltrates (with epidermal alteration) Eosinophils absent Sjogren's syndrome (occasional case) Mixed connective tissue disease Systemic lupus erythematosus (rare case) Discoid lupus erythematosus Relapsing polychondritis Jessner's lymphocytic infiltrate (rare case) Polymorphous light eruption (superfical and deep variant) Malignant lymphoma, T-cell type, including patch and early plaque-stage mycosis fungoides) Pseudolymphoma, including: Lymphomatoid connective tissue diseases Persistant light reactors ("actinic reticuloid") Eosinophils present Erythema multiforme Delayed type hypersensitivity reaction (rare case) Polymorphous light eruption (superfical and deep variant) Lupus erythematosus, drug-induced Malignant lymphoma, T-cell type, including late plaque stage and tumor stage mycosis fungoides) Pseudolymphoma, including: Lymphomatoid hypersensitivity reactions to: Drugs Insect bites (including "Woringer-Kolopp disease") Contactants Viruses (including herpetic infundibulofolliculitis) Light ("actinic reticuloid") Histiocytic dermal infiltrates (with minimal or no epidermal alteration) Palisading necrotizing granulomatous dermatitis Necrobiosis lipoidica Granuloma annulare Rheumatoid nodule Juxta-articular nodes (spirchetal infection) Necrobiosis lipoidica-like tissue reactions in systemic disease Granuloma annulare-like tissue reactions in systemic disease Morphea and morpheiform tissue reactions Histiocytopathic drug reactions Histiocytopathies Histiocytic dermal infiltrates (with epidermal alteration) Histiocytopathic drug reactions Histiocytopathies related to mycoplasma, parvovirus, Epstein-Barr virus, and post-Herpetic eruptions Post-Streptococcal id reactions Connective tissue diseases with morpheiform tissue reactions, including: Lichen sclerosis/morphea overlap Lupus erythematosus Mixed connective tissue disease Neutrophilic/eosinophilic dermal infiltrates With epidermal alteration Pustular hypersensitivity states (i.e. drug eruptions, post-viral acropustulosis of infancy) Pustular follicular reactions, including Pyodermatous eosinophilic folliculitis Pyoderma gangrenosum Drug reactions (i.e. Dilantin hypersensitivity syndrome) Cellulitis Herpes gestationis Without epidermal alteration Urticaria Physical Neutrophilic Cholinergic Granuloma faciale The Subcutis: Septal panniculitis Erythema nodosum Morphea profunda Lobular panniculitis Erythema induratum (of Bazin) Lupus profundus and the other connective tissue diseases including: Behcet's disease Sjogren's syndrome Relpasing polychondritis Pancreatic panniculitis Weber-Christian disease Panniculitis of Rothman-Makai Factitial panniculitis Nodular vasculitis